Is there a reason that I think my car feels slower?
lol..

I'm pretty sure its faster and it sounds like a beast now.. a little louder than the setup I had before and with more of a growl.

They used 2" piping where the pipes go over the rear suspension components and like 2.25" piping coming from the cats and heads..
I THINK... if I remember correctly..

Does anyone know if there is ANY reason the car would lose hp after putting the x-pipe in and removing the secondary mufflers?

 

describe "slower".
Not an X-type expert, but generally speaking, when you allow the motor to breathe (better exhaust flow) you will sacrifice a little on the bottom end where the tuned exhaust is important to the cylinder scavenging, but you will see gains on the top end.
So if it seems less "quick", that could be normal losses.

 

Yes a little less quick...
lol..
but also say im at 3-4k in 2nd and mash the pedal... i dont have as much as a neck snapping effect that I did before.. or maybe Im just going crazy..

But thats no good if its normal...
I wanted the take off to be faster as well

 

do a hard reboot of the cars ecus by disconnecting the negative battery cable and touching to the still connected positive. This clears adaptive, and long termo fuel trim that the ecu LEARNS, as you drive. Right now your oprating under old conditions and adaptations. A hard reset clears these and allows the ecu to reset to default factory setting and relearn. It may not do much as to reap the best rewards from modifications the ecu's software needs to be rewriten, (Tuned). The factory wants safe powertrain operation, low emmissions, good fuel economy, and operation that the "majority" of the Jaguar drivers want. You want something outside these parameters and all the bolt on will never reach their true performance capabilties till the car and ecu is tuned for better fueling, timing and mods

 

I have to agree with Bo...leave well enough alone...

 

This may be the ONLY time I will ever find myself saying this:
I AGREE WITH BO. [:@]
(there. it's outta my system )

I'm all about modifying your car. But this is specifically NOT a performance-oriented platform, and no amount of bolt-on mods are going to make it a stop-light rocket.

But I'm wondering if you did any homework on the exhaust system prior to buying it? Did you get any information on what to expect from it? And if you did, is what you're experiencing different from what was advertised? If so, then I'd contact the manufacturer / seller and discuss it with them.

Either way: good luck.

 

As Brutal said to take advantage you need tuning. Good luck with finding someone to tune the thing. So if I'm understanding correctly you did an x-pipe and straight pipes from the cats to the back of the car? If so how does this affect the car that much? Wouldn't it just affect the sound? Especially considering there are still cats which connect to the 02 sensors which monitor/control things? Or did you add the x-pipe before the cats?

 

What type of exhaust did you put in? The x pipe, correct me if I am wrong, was used to eliminate drone. I had a double x pipe on my lincoln mark viii with a custom magnaflow system on it. Reducing the pipe size would create more back pressure if anything but it sounds like you may have lost back pressure?

edit

Maybe the car needs more air?

 

Christo:
I can't imagine for a moment that he reduced pipe size, but rather increased it. I have not checked, but I would be terribly surprised if the factory stuff was as big as 2" or 2-1/4".
Anyone know the size of the factory pipe from the heads to the cats? and cat-back?

MAny years ago, the hot-rod tuners and Smokey Yunik's of the world learned that in a true dual exhaust system, some pipe lengths were so long that some firing orders suffered from the exhaust pulses actually backing-up on themselves and SLOWING the exhaust. We started using 'H' pipes to alleviate this.
This idea eventually evolved into the 'X' pipe.
X-pipes have been developed to use one exhaust pulse to 'pull' the next one form the other side of the motor, increasing cylinder scavenging.
This all changed the sound as well, from a true "duallie" sound of "blub...blub....blub...." to more of a "burbleburbleburbleburble" (it's spelled funny, but try to say it... )
But the sound was merely a by-product of the performance gain they were looking for.

 

No I didnt decrease the size of the pipes.
I'll hard reset the ecu and see what happens.

and Im modifying it cuz i like making my car my own!
I know its a lazy jag but my lazy jag can beat rx-8s in a stoplight race AND on the freeway!
lol

 

There's a good chance you lost some torque with the X-Pipe at lower RPM but gained power at higher RPMs. I used to drive an 04 Mustang GT. A common modification was to switch out the stock H pipe for an aftermarket X pipe. First thing after the modification everyone would come on the forums and complain that the car was slower with the X pipe. Dyno tests then confirmed that the X-pipe does lower the torque at low RPM which made the car feel slower. All of that was gained back and then some at higher rpm but in ordinary driving you miss out on that. I believe the issue was that of backpressure, you need some of it at lower rpm. The X pipe is more free flowing and thus reduces back pressure too much at lower RPM.

I know that they're two completely different motors but the principle should still be the same.

 

That's cool. I'm down with modifying it any way you want to. **** on what we all tell ya!

But I'll tell ya THIS, (in my really, really quiet voice) If you're beating RX8's in ANY kind of race.... there's more to the story than you're telling us.
The RX8 is a pretty potent platform. I spent most of a day in one at the racetrack, and I can tell you that no Jag that I've ever driven is a match for it, unless HIGHLY modified. Very highly modified.
But you also won't get the comfort out of the RX8 that you will the Jag.

 

I am suprised the 2 inch pipes in the rear did not create some back pressure or at least negate the loss created by the x pipe...

 

why would you assume a 2" pipe would create backpressure?

 

I just figured that going from the 2.5 inch pipes to 2 inch in the rear would create a bottle neck, slowing down the flow - no?

 

well, not always, but yes, your theory is correct.

Early in this thread, I asked if anyone knew the diameter of the factory pipes, but there was no response. Do you know for a fact that the factory pipes are 2-1/2"?

Also, Rosemont83 says he's not sure if he remembers correctly the diameter of his new pipes. AND he states in his most recent post that he did NOT reduce the diameter of the pipes.

I don't know what brand pipes he's using, he hasn't said (Or I missed it), So we can't verify. But I can only imagine a few very specific cases where an aftermarket exhaust manufacturer would be selling a pipe SMALLER than factory, and I would think that only a well-educated buyer would be looking at those, with specific tuning needs in mind... not your average "Bolt-on" kind of guy.

 

Is the stock exhaust a "true" dual exhaust?

 

WOAH WOAH WOAH what?! A Jaguar cant beat an RX-8???????? RX-8s are terribly slow! hahaha

The S-Type R will run a 13.3 at 106 mph in the 1/4 mile with about a 5 second 0-60 and a 2 second 60 foot ET.

The Mazda RX-8 with a 6-speed manual will realistically run a 15.01 at 91 mph in the 1/4 with about a 5.9 second 0-60 and a 2.3 second 60 ft.

Hell a turbo'd RX-8 has a hard time getting in the low 13s..

The RX8 has a 1.3 liter engine... the jaguar has a 4.2 liter engine with an eaton supercharger.. like the saying goes: there is no replacement for displacement..

 

Okay smarty-pants....
I've never driven an S-Type R. So I'm off the hook!
However, let's be fair: An S-Type R can 'realistically' (your word) run a 13:6, not 13:3, and the RX8 is regularly doing 14:4's in factory trim.
And I'd get pretty familiar with the Wankel Rotary before I started dismissing the motor because it's 1.3 liters. Somehow that argument hasn't impressed the folks they race against. Don;t forget that each rotor in a twin rotor motor is firing 3 times per revolution, for 6 firing sequences per revolution of the crank, as opposed to each cylinder in a piston motor firing once for every 2 revolutions of the crank... for 3 firing sequences per revolution of the crank.

And I guess I tend to think very little of straight-line racing. It's rather unimpressive to me, as I am living proof that it ain't that difficult to build an 9 second car.....
I'm much more interested in road course racing. That is MUCH more impressive to me. And I'd still wager on the RX8 over the S-Type R... but as I say, I've no seat time in the S-Type R.

But I DID say "Any kind of race" in my previous post... so I'll have to suck on my teeth and admit that I over-spoke myself... and you are absolutely correct that I was wrong to place such a blanket statement. (Wow... it's REALLY, REALLY hard for me to say I was wrong.... [:@] )

But I WILL come back to the original idea that an X-type should NOT be winning races against an RX8....